The present disclosure relates to improved dispenser valves for a fluid dispenser and dispensing nozzle or pump tips employing the same. The valves and nozzle tip assembly in accordance with the present development may advantageously be employed in connection with a dispenser of a bag-in-a-box type and will be described herein primarily by way of reference thereto. However, it will be recognized that the valve and nozzle tip may also be used in connection with all manner of fluid types and fluid dispensers. In a preferred embodiment, the present disclosure relates to an improved liquid pump tip assembly for fluid dispenser and, specifically, to a tip assembly which utilizes an interiorly received resiliently flexible valve. In a further aspect, liquid dispensers incorporating the same are provided.
Liquid and semi-liquid dispensers are used in numerous applications and are used to dispense metered portions of soaps, creams, lotions, gels, and similar flowable materials. Such dispensers are commonly found in public restrooms, medical facilities, or the like and may be manually operated or may be powered units which may operate automatically, e.g., under preprogrammed control in response to sensory input.
Commonly, bag-in-box dispensing systems include a housing, such as a wall-mounted housing, and a disposable or reusable dispensing system. The disposable dispensing system includes a disposable pump assembly coupled to a flexible, collapsible bag or a semi rigid, unvented, bottle containing a supply of product to be dispensed. The reusable dispensing system includes a rigid or semi rigid refillable reservoir that is vented to the atmosphere and fitted with a pump as described herein. Although a wide variety of pump mechanisms have been developed, they generally include a resiliently flexible or deformable chamber having an inlet fluidically coupled to the bag or other container and a dispensing outlet having a spring loaded valve.
The spring loaded valve is normally closed and includes a spring and ball within the flow passageway, wherein the spring urges a ball into sealing engagement with the pump outlet. Commonly, the chamber is of a tube-type having a resiliently collapsible pump tube with its first end coupled to the bag or other container and the second end coupled to a pump tip for accurately dispensing a quantity of fluid, e.g., into the hand of a user.
In the tube-type pumps, the pump tip includes a ball and spring check valve in which a ball is seated against the inlet of the tip by a spring. In operation, the tube is compressed and the fluid moves the ball out of the seated position, compressing the spring, and thereby allowing the fluid to be dispensed to flow around the ball and through the tip. A one-way valve may be provided at the first tube end to prevent soap in the tube from reentering the bag or other container when the tube is compressed. Such dispensers are described in the present applicant's prior U.S. Pat. Nos. 6,286,732, 5,598,952, 5,501,372, and 5,464,125, each of which is incorporated herein in its entirety.
Another type of pump is a so-called bubble, dome, or disc pump wherein the resiliently flexible chamber is hemispherical or dome shaped, and may be of the type described in my prior U.S. Pat. No. 6,394,316, which is incorporated herein by reference in its entirety.
In operation, a lever or other actuator on the housing is depressed to collapse the deformable chamber to increase the pressure in the chamber. The increased pressure in the chamber displaces the ball and liquid passes through the pump outlet, around the ball, and is expelled. When the actuator is released, the chamber returns from the collapsed state to its original volume, thereby decreasing the pressure within the chamber, thereby causing the ball to return to the seated position and to draw an additional charge of product from the bag or other container into the chamber.
A one-way check valve may also be provided at the dispensing pump inlet to permit flow from the bag into the collapsible chamber, but to prevent product in the chamber from flowing back into the bag or other container when the actuator is depressed. For example, a ball may be held in close proximity to the pump inlet via a perforated retainer. When the pressure in the chamber increases, the ball is seated against the pump inlet, thereby preventing flow of product from the chamber back into the bag. While the chamber returns to its original volume, the reduced pressure unseats the check ball and allows product to pass from the bag or other container, through the pump inlet and around the ball through the perforated ball retainer. In the disposable dispensing system, the bag or non-vented semi-rigid container collapses upon itself, thereby maintaining constant pressure within the bag. In the reusable dispensing system, the rigid or semi rigid container is vented to maintain balance between internal and atmospheric pressures and, as such, does not collapse during evacuation.
A common problem with the ball and spring dispenser valves is that they tend to clog and become unusable, particularly when liquid product containing particulate matter is used, or for highly viscous liquids.
In FIG. 29, there is shown a known dispenser tip incorporating a resiliently flexible cross-slit valve 1340 instead of the conventional ball and spring check valve. The dispenser tip includes a body 1334, a tube coupling 1335, and an integrally formed, perforated internal baffle 1354. The cross-slit valve 1340 is retained within an outlet end 1337 of the dispenser tip on the downstream side of the perforated baffle 1354. An external retainer ring 1339 is secured to the outlet end 1337 to secure a peripheral portion 1344 of the valve 1340 within the tip outlet end 1337 between the ring 1339 and an interior shoulder 1341. In one embodiment, a snap fit engagement of the retainer ring 1339 within the tip outlet end 1337 was found by the present applicant to exhibit unacceptable levels of stress cracks and splitting. In a further embodiment, the snap fit engagement between the retainer ring 1339 within the tip outlet end 1337 was replaced with an ultrasonic weld; however, this process adds expense and has shown other problems including excessive weld flash.
Accordingly, a need exists for an effective pump tip assembly incorporating a flexible, resilient valve with an internally applied retainer ring that solves the above-referenced problems, is easy to manufacture, and lowers production cost.